MailChimp Product Recommendations - Easily build automated personalized email marketing
Depict.ai - Amazon-quality product recommendations for any online store
Metisa - Product recommendations that learn as your customers shop
MarsBot - Local recommendations based on where you go. By Foursquare.
Suto - Get one-on-one expert product recommendations.
PH Bench for Chrome - Get product recommendations and benchmarking while browsing